I wrote following program.
When in the initial screen user presses F8 button 'FD01' transaction is called.
When user finish working with this transaction my program redirects him
to transaction 'FK01'. When user finish working with transaction 'FK01' my
program returns him to initial screen of my program. if user tries to fulfil this sequence of operations again then when hi finish processing 'FD01' program
doesn't redirect to transaction 'FK01'.
I can't understand why my program sometimes works, sometimes doesn't.